US20010043291A1

US20010043291A1 - Screen input type display device

Info

Publication number: US20010043291A1
Application number: US09/838,213
Authority: US
Inventors: Masao Kono; Akira Kakinuma; Koji Ishii; Haruhisa Otsuka; Kazuo Ishii
Original assignee: Hitachi Device Engineering Co Ltd; Hitachi Ltd; Hitachi Chiba Electronics Ltd
Current assignee: Hitachi Ltd; Hitachi Chiba Electronics Ltd; Japan Display Inc
Priority date: 2000-05-17
Filing date: 2001-04-20
Publication date: 2001-11-22
Also published as: KR100424427B1; KR20010106252A; CN1325054A; JP2002041231A; CN1235124C; US6721019B2; TWI284228B

Abstract

The task of the present invention is to provide a highly reliable screen input type display device using a touch panel which can facilitate the control of a gap formed between upper and lower substrates and can stabilize the linearity of the resistance value detection of a resistance film whereby an erroneous operation of the coordinates detection can be eliminated. To solve such a task, a tape-like conductive pressure sensitive adhesive member which is formed by sandwiching a metal foil with conductive pressure sensitive adhesive material is used at a connection portion between an upper wiring electrode mounted on an upper resistance film formed on an upper substrate and an inter-substrate connection wiring electrode formed on a lower substrate.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a screen input type display device having a constitution in which a touch panel which detects input coordinates based on the change of resistance by a push manipulation is laminated.

2. Description of the Related Art

As an example of a display device, a liquid crystal display device which is used as display means of a personal computer or as other monitor is known. This display device irradiates illumination light to images formed on a liquid crystal panel and visualizes the images by irradiating a transmitting light or a reflection light to a display surface side.

In general, a screen input type display device which adopts this type of liquid crystal display device uses a liquid crystal panel which sandwiches a liquid crystal layer in a space defined between a pair of laminated substrates having pixel selecting electrodes and the like and can generate images by changing the orientation state of liquid crystal molecules corresponding to selected pixel portions. Since the generated image per se is not in the visible state, the liquid crystal panel is irradiated by giving light from outside and a transmitting light or a reflection light therefrom is observed.

Recently, an information terminal which uses this type of liquid crystal display device as display means and is provided with a touch panel which is laminated on a screen of the liquid crystal display device and inputs various information through the screen by a push manipulation has been widely used.

Although there exist touch panels of various systems depending on operation principles, the most popular touch panel is one which adopts a system in which input coordinates are detected depending on a change quantity of resistance, a so-called “analogue resistance film system”.

In this touch panel of this analogue resistance film system, one substrate which becomes an information input side is constituted of a soft film such as a transparent plastic sheet or the like, the other substrate is constituted of a transparent hard plate preferably made of glass, and resistance films are respectively provided to opposing surfaces of two transparent substrates. Due to such a constitution, a two dimensional coordinates value is detected based on the resistance value between resistance films of respective substrates which are brought into contact with each other with the push manipulation applied from one substrate side and an output terminal.

FIG. 18 is a schematic cross-sectional view for explaining an example of an overall constitution of a screen input type display device which constitutes a display device provided with a touch panel. This display device is constituted by laminating a

touch panel

100 on a liquid crystal panel 300. Although the illustrated display device is of a type which inserts an auxiliary light source device 200 between the liquid crystal panel 300 and the touch panel 100, a display device which mounts the auxiliary light source device on a side opposite to a display screen of the liquid crystal panel 300 or a display device which is not provided with the auxiliary light source device has been commercialized. In the drawing, numeral 202 indicates a lamp which constitutes the auxiliary light source device 200 and numeral 203 indicates a lamp reflection sheet which also constitutes the auxiliary light source device 200.

FIG. 19A and FIG. 19B are schematic cross-sectional views for explaining the constitution and the state at the time of push manipulation of an essential part of a signal input side of the touch panel shown in FIG. 18. Although the upper substrate is referred as a first substrate and the lower substrate is referred as a second substrate for facilitating the explanation, these substrates may be arranged up side down.

In FIG. 19A and FIG. 19B,

numeral

2 indicates an upper substrate made of a transparent film such as plastic or the like and numeral 3 indicates a lower substrate made of a hard plate such as a glass plate. On inner surfaces of these two

substrates

2, 3, an upper resistance film 4 and a lower resistance film 5 which are respectively preferably made of ITO are formed as a coating. Further, in an input region AR of the lower resistance film 5 which is formed on the lower substrate 3, dot-like spacers 9 which prevent upper and

lower resistance films

4, 5 from coming into contact with each other in the non-input manipulation state are formed. The spacers 9 are formed by printing using a mask having given apertures or a photolithography technique or the like of a photosensitive resin.

In an adhesion region (seal region) SL which is located at an outermost periphery of the touch panel, the

upper resistance film

4 is electrically connected to an upper wiring electrode 6 which is formed on the upper resistance film of the upper substrate and an inter-substrate connection wiring electrode 7 which is formed on the lower substrate. The inter-substrate connection wiring electrode 7 is connected to a coordinates recognition circuit disposed outside by a outgoing line (generally, a flexible printed circuit board: FPC) not shown in the drawing by way of a pull-around wiring not shown in the drawing. The lower resistance film 5 which is formed on the lower substrate 3 is connected to a lower wiring electrode not shown in the drawing and the lower resistance film 5 is connected to the outgoing line by way of a pull-around wiring not shown in the drawing which is formed on the inner surface of the lower substrate 3.

The

upper wiring electrode

6 and the inter-substrate connection wiring electrode 7 are respectively coated with protective films (insulation films) 12A, 12B and these protective films are adhered to each other by means of a seal agent (adhesive agent or adhesive sheet) 13.

In the inside of the seal region SL, the input region AR is positioned by way of an inoperable region NR. The inoperable region NR is a portion which becomes insensitive at the time of performing the push input manipulation. As shown in FIG. 19B, this inoperable region NR corresponds to an input invalidation space which is formed when the

upper substrate

2 is deflected toward the lower substrate 3 upon receiving the press pressure of a nib 56 which constitutes input means.

In general, in this inoperable region NR, an inoperable

region forming member

14 is provided to prevent an input failure of information by the push input manipulation of the nib 56. That is, the inoperable region forming member 14 having a size which ensures the entrance of the nib 56 in the input region AR in the state shown in FIG. 19B and is made of transparent insulation material is provided to the inoperable region NR.

FIG. 20 is a schematic cross-sectional view for explaining the constitution of an essential part of a connection portion between the

upper wiring electrode

6 and the inter-substrate connection wiring electrode 7 of the touch panel. The upper wiring electrode 6 formed on the upper resistance film 4 on the inner surface of the upper substrate 2 and the inter-substrate connection wiring electrode 7 formed on the inner surface of the lower substrate 3 are electrically connected with each other by way of an adhesive agent 14 made of epoxy resin in which metal particles are mixed.

In the conventional screen input type display device provided with the touch panel having such a constitution, conductive thin films made of silver paste or the like which are coated on the upper and lower wiring connection portions and the adhesive agent in which the metal particles are mixed are used and hence, when a gap between the upper and lower substrates is set to approximately 40 μm to 150 μm, it is difficult to control such a gap. When the gap between the upper and lower substrates is not uniform, a user has a discomfort in his input feeling at the time of performing the push manipulation. This has been one of tasks to be solved by the present invention.

Further, since the

adhesive agent

14 in which the metal particles are mixed is used for the connection between the upper wiring electrode 6 formed on the upper resistance film 4 of the upper substrate 2 and the inter-substrate connection wiring electrode 7 formed on the lower substrate 3, the irregularities are liable to be generated in the connection resistance and it is difficult to stabilize the linearity of the detected resistance value. This brings about an erroneous operation. To reduce this erroneous operation, the load which a coordinates detection circuit must bear becomes large. This also has been a task to be solved for enhancing the reliability of the screen input type display device.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a screen input type display device using a touch panel having a high reliability which can solve the above-mentioned tasks the prior art, can easily perform a gap control between an upper and lower substrates, can stabilize the linearity of the resistance value detection with the use of the resistance films and can eliminate the erroneous operation of the coordinates detection.

To achieve the above-mentioned object, for establishing the connection between a wiring electrode connected to a resistance film of a first substrate and an inter-substrate connection wiring electrode formed on a second substrate, the present invention adopts a planar (or tape-like) structural body which sandwiches a metal foil between conductive pressure sensitive adhesive agents, that is, a conductive pressure sensitive adhesive member which coats the conductive pressure sensitive adhesive agents on both surfaces of the metal foil. The resistance film of the first substrate may be directly brought into contact with the conductive pressure sensitive adhesive member without interposing a wiring electrode therebetween.

Further, as conductive material contained in the conductive pressure sensitive adhesive agent, metal particles preferably made of copper particles or alternatively plastic particles or glass particles which have a metal plating made of nickel, gold or other metal formed on surface thereof can be used.

With the use of the structural body having such a constitution, since the resistance film of a first substrate or the wiring electrode which is connected to the resistance film and the inter-substrate wiring electrode formed on the second substrate are electrically connected by a face contact, the stability of the contact resistance is achieved. Accordingly, the linearity of the resistance value detection is improved so that the erroneous operation of the coordinates detection can be obviated and a load that a coordinates detection circuit must bear can be reduced.

Further, according to the constitution of the present invention, by changing a thickness of the metal foil, the gap between the first substrate and the second substrate (upper and lower substrates) can be arbitrarily, accurately and uniformly controlled, and the input feeling can be enhanced.

The present invention adopts a structural body (conductive pressure sensitive adhesive member) which is formed by coating pressure sensitive adhesive material in which metal particles are mixed on one surface of a metal foil and coating pressure sensitive adhesive material in which conductive particles formed by applying a metal plating on surfaces of plastic particles or conductive particles formed by applying a conductive metal plating on surfaces of glass particles are mixed on the other surface of the metal foil.

Then, the above-mentioned one surface is made to face the first substrate in an opposed manner and the other surface is made to face the second substrate in an opposed manner. Due to such a constitution, by making use of collapsing or embedding of the conductive particles, the direct contact area between the conductive particles and the conductive pressure sensitive adhesive members formed on the inner surface of either one or the other substrate or between the conductive particles and the resistance films can be increased. Here, the formation of the wiring electrode on the first substrate side can be omitted. Further, by directly embedding the conductive particles into the wiring electrode or the resistance film formed on the inner surface of one substrate, the direct contact area can be increased and the gap can be accurately set.

The above-mentioned one substrate and the other substrate respectively constitute the first substrate and the second substrate and either one of these substrates constitutes an input-side substrate, that is, an upper substrate of a touch panel which becomes a product or a substrate opposite to the input-side substrate, that is, a lower substrate of the touch panel.

As a display device used as a screen input type display device according to the present invention, a liquid crystal display device which uses a liquid crystal panel of a so-called “passive matrix type”, “active matrix type” or other known type can be used. Further, the present invention is not limited to the reflection-type liquid crystal display device and is applicable to a transparent-type or a semitransparent/reflection type liquid crystal display device. Further, the present invention is not limited to the liquid crystal display device and is applicable to other display devices.

The constitution of the screen input type display device of the present invention which laminates the touch panel is not limited to the constitution described in “what is claimed is” and the constitutions of embodiments which will be explained later. That is, the constitution of the screen input type display device of the present invention is also applicable to any conductive connection between a first substrate and a second substrate of a touch panel of a system which detects coordinates based on the change of capacity between the first and second substrates or change of other electric quantity or of a digital system. In this manner, various modifications are conceivable without departing from the technical concept of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an developed perspective view for explaining the entire constitution of a first embodiment of a touch panel which constitutes a screen input type display device according to the present invention; [0029]
FIG. 2 is a cross-sectional view taken along a line A-A of FIG. 1; [0030]
FIG. 3 is a schematic cross-sectional view for explaining a first example of conductive pressure sensitive adhesive member formed in a seal region of the first embodiment of the present invention; [0031]
FIG. 4 is a schematic cross-sectional view for explaining a third example of conductive pressure sensitive adhesive member formed in a seal region of the first embodiment of the present invention; [0032]
FIG. 5 is a developed perspective view for explaining the entire constitution of a second embodiment of a touch panel which constitutes a screen input type display device according to the present invention; [0033]
FIG. 6 is a schematic cross-sectional view of an essential part taken along a line B-B of FIG. 5 for explaining the constitution of a seal region of the second embodiment of the present invention in an enlarged form; [0034]
FIG. 7 is a cross-sectional view for schematically explaining the structure of a first example of a conductive pressure sensitive adhesive member in FIG. 6; [0035]
FIG. 8 is a cross-sectional view for schematically explaining the structure of a second example of a conductive pressure sensitive adhesive member in FIG. 6; [0036]
FIG. 9 is a cross-sectional view for schematically explaining the structure of a third example of a conductive pressure sensitive adhesive member in FIG. 6; [0037]
FIG. 10 is a schematic cross-sectional view for explaining the constitution of an essential part of a third embodiment of the touch panel constituting the screen input type display device of the present invention; [0038]
FIG. 11 is a schematic cross-sectional view similar to that of FIG. 6 for explaining the constitution of a conductive pressure sensitive adhesive member of a fourth embodiment of the touch panel constituting the screen input type display device of the present invention; [0039]
FIG. 12 is an explanatory view for explaining the manufacturing steps of a touch panel used in the screen input type display device of the present invention; [0040]
FIG. 13 is a cross-sectional view for explaining one mode for carrying out a screen input type display device of the present invention; [0041]
FIG. 14 is a cross-sectional view for explaining other mode for carrying out a screen input type display device of the present invention; [0042]
FIG. 15A-FIG. 15E are views of an outer appearance of the screen input type display device of the present invention as viewed from five directions; [0043]
FIG. 16A-FIG. 16D are cross-sectional views of an essential part of FIG. 15A-FIG. 15E; [0044]
FIG. 17 is an explanatory view of one example of an information processing device which uses the screen input type display device of the present invention; [0045]
FIG. 18 is a schematic cross-sectional view for explaining a schematic constitutional example of a screen input type display device which constitutes a display device having a touch panel; [0046]
FIG. 19A and FIG. 19B are schematic cross-sectional views for explaining the constitution of an essential part of a signal output side of the touch panel shown in FIG. 18 and the state of the touch panel at the time of performing the push manipulation; [0047]
FIG. 20 is a schematic cross-sectional view for explaining the constitution of an essential part of an upper and lower wiring connection portion of the touch panel shown in FIG. 19A and FIG. 19B.[0048]

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The modes for carrying out the invention are explained in detail hereinafter in conjunction with embodiments where an analogue type touch panel which detects the change of resistance is described as an example. [0049]
FIG. 1 is a developed view showing an entire constitution of a first embodiment of a touch panel which constitutes a screen input type display device of the present invention. Further, FIG. 2 is a cross-sectional view taken along a line A-A of FIG. 1. [0050]
On inner surfaces of a first substrate [0051] 2 (hereinafter called “upper substrate”) made of polyethylene telephthalate (PET) film and a second substrate (hereinafter called “lower substrate”) 3 made of glass, a first resistance film (hereinafter called “upper resist film”) 4 made of ITO (Indium Tin Oxide) and a second resistance film (hereinafter called “lower resistance film”) 5 are respectively formed as a coating.
In an input region AR of a [0052] lower resistance film 5 formed on the lower substrate 3, dot-like spacers 9 which prevent the upper and lower resistance films 4, 5 from coming into contact with each other in a non-input manipulation state (ordinary state) are formed. These spacers 9 are formed by printing using a mask having given apertures or by a photolithography technique using a photosensitive resin or the like. The arrangement interval of the spacers 9 is set greater than the width of a nib which constitutes press means.
The [0053] upper resistance film 4 is electrically connected to an upper wiring electrode 6 which is formed by printing or the like in a seal region SL and is preferably made of a silver paste, while the upper wiring electrode 6 is electrically connected to an inter-substrate connection wiring electrode 7 through a conductive pressure sensitive adhesive member 8. This inter-substrate connection wiring electrode 7 is pulled around by means of an inter-substrate connection wiring electrode pull-around wiring 17 formed on the lower substrate 3 to a side (output side) where an FPC 11 is adhered with pressure and is connected to a coordinates recognition circuit disposed outside through an outgoing line carried by the FPC 11.
In the seal region disposed at a side opposite to the side (output side) where the [0054] FPC 11 is formed, the conductive pressure sensitive adhesive member 8 is interposed between the upper wiring electrode 6 and the inter-substrate connection wiring electrode 7 so that the upper wiring electrode 6 and the inter-substrate connection wiring electrode 7 are electrically connected with each other by bridging and the upper and lower substrates are adhered to each other.
On the other hand, [0055] lower wiring electrodes 16 are respectively provided to both end portions of the lower resistance film 5 formed on the inner surface of the lower substrate 3 and are respectively pulled around toward the output side through lower wiring electrode pull-around wiring 18. The upper resistance film 4 is formed such that the film 4 terminates in front of positions where the upper resistance film 4 and the lower wiring electrodes 16 are superposed. Accordingly, they are electrically insulated from each other.
FIG. 3 is a schematic cross-sectional view for explaining a first example of the conductive pressure sensitive adhesive member provided to the seal region in the first embodiment of the present invention. This conductive pressure sensitive [0056] adhesive member 8 is formed by coating pressure sensitive adhesive material 8B in which conductive particles 8C are mixed on both surfaces of a metal foil 8A. Although a low-resistance metal such as a copper foil, aluminum foil or the like can be used as the metal foil 8A, the copper foil is used in this embodiment. Here, it is needless to say that a non-metallic good conductor can be used.
Although organic material made of acrylic-based material or the like or rubber-based material can be used as the pressure sensitive adhesive material [0057] 8B, the acrylic resin is used in this embodiment. Further, although the copper foil is used as the metal foil 8A in this embodiment, the similar advantageous effect can be obtained with the use of the aluminum foil. Further, as the conductive particles 8C which are mixed into the pressure sensitive adhesive material 8B, any one of particles made of copper, aluminum, nickel, or stainless steel can be used. In this embodiment, copper particles are used. The same goes for following embodiments.
According to this embodiment, the electric connection between the [0058] conductive particles 8C and the upper wiring electrode 6, the inter-substrate connection wiring electrode 7 and the metal foil 8A can be improved and the uniformity of the gap is ensured. In the conventional touch panel, since the above-mentioned lamination is performed by adhesion, when the displacement occurs between the upper wiring electrode 6 and the inter-substrate connection wiring electrode 7 due to an application of an external force, it is difficult to return them to an original position. However, according to this embodiment, since means which laminates the first and second substrates while ensuring the electric connection between them is the pressure sensitive adhesion by the conductive pressure sensitive adhesive member 8, when an external force is applied to displace one of two substrates made of the upper and lower substrates from the other, this displacement is allowed to make the both substrates displaced from each other and the electric connection between the upper wiring electrode 6 and the inter-substrate connection wiring electrode 7 is maintained while they are held in the displaced condition. Then, when the external force is removed, the upper wiring electrode 6 and the inter-substrate connection wiring electrode 7 are made to return to the original position.
Further, in a second example of the present embodiment, as the [0059] conductive particles 8C shown in FIG. 3, conductive particles which are formed by applying a metal plating made of nickel or gold on surfaces of hard plastic particles preferably made of PET (polyethylene telephthalate) are used.
When the conductive particles which are formed by applying the metal plating on surfaces of the plastic particles are used, at the time of laminating the upper substrate which constitutes the first substrate and the lower substrate which constitutes the second substrate and forming a gap between these substrates, the plastic particles are collapsed due to the press force at the time of forming the gap. Accordingly, the contact areas of the conductive particles to the [0060] upper wiring electrode 6, the inter-substrate connection wiring electrode 7 and the metal foil 8A are increased and hence, the irregularities of the resistance values are reduced whereby an advantageous effect that the linearity of the resistance value detection can be made stable is obtained. Simultaneously, the allowance of the displacement of the upper wiring electrode 6, the inter-substrate connection wiring electrode 7 due to the external force and the return of the upper wiring electrode 6, the inter-substrate connection wiring electrode 7 to the original position can be obtained as in the case of the first example.
FIG. 4 is a schematic cross-sectional view for explaining a third example of the conductive pressure sensitive adhesive member formed in the seal region of the first embodiment of the present invention. With respect to this conductive pressure sensitive [0061] adhesive member 8, large-diameter conductive particles 8E are embedded in the pressure sensitive adhesive material 8D and these large-diameter conductive particles 8E control the gap defined between the upper and lower substrates in place of the metal foil in the above-mentioned example. As the conductive particles 8E, conductive particles which are made of metal particles such as copper particles or the like are formed by applying a metal plating made of gold, nickel or the like around large-diameter plastic particles and those used in the above-mentioned example can be used in the same manner.
When the large-diameter metal particles are used, the metal particles are embedded into the [0062] upper wiring electrode 6 and the inter-substrate connection wiring electrode 7 coated on the inner surfaces of the upper and lower substrates due to a press force at the time of forming the gap between the upper and lower substrates so that the contact area thereof is increased and hence, the contact resistance becomes more uniform.
Further, when the metal particles which are formed by applying the metal plating made of gold, nickel or the like around large-diameter plastic particles, the plastic particles are collapsed due to a press force at the time of forming the gap between the upper and lower substrates so that the contact area thereof is also increased and hence, the contact resistance also becomes more uniform. [0063]
According to this example, the electric contact between the [0064] upper wiring electrode 6 and the inter-substrate connection wiring electrode 7 disposed between the upper and lower substrates is also enhanced so that the irregularities of the resistance value are reduced and an advantageous effect that the linearity of the resistance value detection can be made stable is obtained. Further, the allowance of the displacement between the upper wiring electrode 6 and the inter-substrate connection wiring electrode 7 due to an external force and the return of them to the original position can be realized.
With the provision of the constitution of the touch panel explained in the above-mentioned first embodiment, the erroneous operation of the coordinates inputted through the screen can be prevented so that it becomes possible to provide a screen input type display device which can realize a highly reliable screen inputting. [0065]
FIG. 5 is a developed perspective view for explaining an entire constitution of the second embodiment of a touch panel which constitutes a screen input type display device of the present invention. In the drawing, numerals [0066] 6A, 6B indicate upper wiring electrodes, numerals 7A, 7B indicate inter-substrate connection wiring electrodes formed on the inner surfaces of the lower substrate 3, numeral 80 indicates conductive pressure sensitive adhesive members which electrically connect the wiring electrodes 6A, 6B of the upper substrate 2 and the inter-substrate connection wiring electrodes 7A, 7B at seal portions of the upper and lower substrates. Parts having the same numerals with those shown in FIG. 1 correspond to identical functional parts.
In this embodiment, an [0067] upper resistance film 4 is formed on the entire surface of the inner surface of the upper substrate 2 and the upper wiring electrodes 6A, 6B are formed on the upper resistance film 4 in the vicinity of both end portions thereof (left and right sides of FIG. 5). Pressure sensitive adhesive tapes 15 make the upper and lower substrates adhere to each other at portions other than portions corresponding to the conductive pressure sensitive adhesive members 80. Although the pressure sensitive adhesive tapes 15 are indicated as L-shaped members in FIG. 5, it is preferable to cut a tape-like member into strips and to adhere them in view of the easiness of operation.
Although the [0068] lower wiring electrodes 16, the lower wiring electrode pull-around wirings 18, the inter-substrate connection wiring electrode pull-around wirings 17 are insulated from the upper resistance film 4 by the pressure sensitive adhesive tapes 15, the insulation structure is not limited to the above and an insulation layers may be separately provided.
Since other constitution of this embodiment is identical with that of the first embodiment which has been explained in conjunction with FIG. 1, the repeated explanation of such a constitution is omitted. [0069]
FIG. 6 is a schematic cross-sectional view of an essential part taken along a line B-B of FIG. 5 which explains the constitution of the seal region in the second embodiment of the present invention in an enlarged form. In this embodiment, the upper wiring electrode [0070] 6A formed on the upper resistance film 4 formed on the entire surface of the inner surface of the upper substrate 2 and the inter-substrate connection wiring electrode 7A formed on the seal region portion of the lower substrate 3 are electrically connected by a conductive pressure sensitive adhesive member 80. The above-mentioned wiring electrode 6A and inter-substrate connection wiring electrode 7A are formed by coating or printing the silver paste.
Here, a conductive pressure [0071] sensitive adhesive member 80 which is interposed between the upper wiring electrode 6B and the inter-substrate connection wiring electrode 7B is formed in the same manner as the conductive pressure sensitive adhesive member 80 which is interposed between the upper wiring electrode 6A and the inter-substrate connection wiring electrode 7A (The same goes for constitutions which will be explained hereinafter).
FIG. 7 is a cross-sectional view for schematically explaining the structure of a first example of the conductive pressure sensitive adhesive member in the second embodiment of the present invention. In this example, the conductive pressure sensitive adhesive member is formed in a taped shape by forming acrylic-based pressure sensitive [0072] adhesive material 80B in which conductive particles 80C are mixed on both surfaces of the metal foil 80A. As the metal foil 80A, a copper foil or an aluminum foil may be used or alternatively rubber-based pressure sensitive adhesive material may be used in place of the acrylic-based pressure sensitive adhesive material.
Due to the constitution of this embodiment, the electric contact between the [0073] conductive particles 80C and the upper wiring electrode 6 (6A, 6B), the inter-substrate connection wiring electrode 7 (7A, 7B) and the metal foil 80A is increased, the uniformity of the gap is obtained, and the electric contact of the upper wiring electrode 6 and the inter-substrate connection wiring electrode 7 disposed between the upper and lower substrates is improved so that the irregularities of the resistance values are reduced whereby an advantageous effect that the linearity of the resistance value detection can be made stable is obtained. Simultaneously, the allowance of the displacement between the upper wiring electrode 6 and the inter-substrate connection wiring electrode 7 due to the external force and the return of the upper wiring electrode 6 and the inter-substrate connection wiring electrode 7 to the original position can be obtained as in the case of the above-mentioned respective examples.
FIG. 8 is a cross-sectional view for schematically explaining the structure of a second example of the conductive pressure sensitive adhesive member in the second embodiment of the present invention. In this example, the conductive pressure sensitive adhesive member is formed in a taped shape by applying acrylic-based pressure sensitive [0074] adhesive material 80B in which conductive particles 80D are mixed to both surfaces of the metal foil 80A. Here, the conductive particles 80D are formed by applying a metal plating on surfaces of hard plastic particles which are preferably made of PET. As the conductive particles 80D, conductive particles to which the metal plating made of nickel or gold is applied can be used. Alternatively, rubber-based pressure sensitive adhesive material may be used in place of the acrylic-based pressure sensitive adhesive material.
Due to the constitution of this example, the electric contact between the [0075] conductive particles 80D and the upper wiring electrode 6 (6A, 6B), the inter-substrate connection wiring electrode 7 (7A, 7B) and the metal foil 80A is improved. Further, in the case that the conductive particles formed by applying a metal plating on surfaces of plastic particles is used as the conductive particles 80D, when the upper and lower substrates 2, 3 are laminated to each other and a gap is formed between both substrates, the collapsing of the plastic particles occurs due to the press pressure at the time of forming the gap.
Accordingly, the uniformity of the gap is obtained, and the electric contact of the [0076] upper wiring electrode 6 and the inter-substrate connection wiring electrode 7 disposed between the upper and lower substrates is improved so that the irregularities of the resistance values are reduced and an advantageous effect that the linearity of the resistance value detection can be made stable is obtained. Further, the allowance of the displacement between the upper wiring electrode 6 and the inter-substrate connection wiring electrode 7 due to an external force and the return of them to the original position can be realized.
With the provision of the constitution of the touch panel explained in the above-mentioned second embodiment, the erroneous operation of the coordinates inputted through the screen can be prevented so that it becomes possible to provide a screen input type display device which can realize a highly reliable screen inputting. [0077]
FIG. 9 is a cross-sectional view for schematically explaining the structure of a third example of the conductive pressure sensitive adhesive member in the second embodiment of the present invention. In this example, the conductive pressure [0078] sensitive adhesive member 80 is formed in a taped shape by forming acrylic-based pressure sensitive adhesive material 80B in which the conductive particles 80C are mixed on the upper wiring electrode 6A side of the metal foil 80A and by forming acrylic-based pressure sensitive adhesive material in which conductive particles 80D which are formed by applying a metal plating on surfaces of hard plastic particles preferably made of PET on the inter-substrate connection wiring electrode 7A side of the metal foil 80A. As the metal foil, a copper foil or an aluminum foil can be used. Alternatively, rubber-based pressure sensitive adhesive material may be used in place of the acrylic-based pressure sensitive adhesive material.
With the use of the conductive pressure [0079] sensitive adhesive member 80 having the structure of this example, when the upper and lower substrates 2, 3 are laminated to each other and a gap is formed between both substrates, the collapsing of the plastic particles occurs due to the press pressure at the time of forming the gap. Accordingly, the contact area of the conductive particles with the upper wiring electrode 6 (6A, 6B), the inter-substrate connection wiring electrode 7(7A, 7B) and the metal foil 80A is increased so that the irregularities of the resistance values are reduced and an advantageous effect that the linearity of the resistance value detection can be made stable is obtained. Further, the allowance of the displacement between the upper wiring electrode 6 and the inter-substrate connection wiring electrode 7 due to an external force and the return of them to the original position can be realized as in the case of the previously-mentioned examples.
FIG. 10 is a schematic cross-sectional view similar to FIG. 6 which explains the constitution of an essential part of a third embodiment of a touch panel which constitutes a screen input type display device according to the present invention. This embodiment is characterized by eliminating the [0080] upper wiring electrode 6 which is coated on the upper resistance film 4 formed on the inner surface of the upper substrate 2 from the constitution explained in conjunction with FIG. 7, FIG. 8 and FIG. 9.
That is, in this embodiment, the conductive pressure [0081] sensitive material 80B in which the conductive particles 80C or 80D of the conductive pressure sensitive adhesive member 80 which face the upper substrate in an opposed manner are mixed is directly adhered to the upper resist film 4.
Due to this embodiment, in addition to the above-mentioned advantageous effects of respective embodiments, a step for forming the upper wiring electrode becomes unnecessary and hence, the reduction of cost can be achieved. [0082]
With the provision of the constitution of the touch panel explained in the above-mentioned third embodiment, the erroneous operation of the coordinates inputted through the screen can be prevented so that it becomes possible to provide a screen input type display device which can realize a highly reliable screen inputting. [0083]
FIG. 11 is a schematic cross-sectional view for explaining the constitution of a conductive pressure sensitive adhesive member of the fourth embodiment of the touch panel which constitutes the screen input type display device of the present invention. In this embodiment, a conductive pressure [0084] sensitive adhesive member 80 is formed by embedding large-diameter conductive particles 80E in pressure sensitive adhesive material 80B. As the conductive particles 80E, plastic particles which apply a metal (gold, nickel or the like) plating on surfaces thereof are used.
These large-diameter conductive particles [0085] 8E are provided for controlling the gap between the upper and lower substrates. By adhering the upper and lower substrates using this conductive pressure sensitive adhesive member 80, the gap between the upper and lower substrates can be controlled. When the conductive particles which form the plating made of metal such as nickel or the like on the surfaces of large-diameter plastic particles are used, the plastic particles are collapsed by a press force at the time of forming the gap between the upper and lower substrates and hence, the contact area is increased and the contact resistance becomes more uniform.
In this embodiment also, the electric contact between the upper and lower substrates is enhanced so that an advantageous effect that the irregularities of the resistance values are reduced whereby the linearity of the resistance value detection can be made stable is obtained. Simultaneously, the allowance of the displacement between the upper wiring electrode and the inter-substrate connection wiring electrode due to an external force and the return of them to the original position can be realized as in the case of the previously-mentioned examples. [0086]
The large-diameter metal particles may be used in place of the [0087] conductive particles 80E which are formed by applying a metal plating on surfaces of large-diameter plastic particles. In this case, the metal particles are embedded into the upper wiring electrode and the inter-substrate connection wiring electrode coated on the inner surfaces of the upper and lower substrates due to a press force at the time of forming the gap between the upper and lower substrates so that the contact area thereof is increased and hence, the contact resistance becomes more uniform.
In this embodiment also, the electric contact between the upper and lower substrates is enhanced so that an advantageous that the irregularities of the resistance values are reduced whereby the linearity of the resistance value detection can be made stable can be obtained. Simultaneously, it becomes possible to obtain an advantageous effect that the mechanical strength of the laminated upper and lower substrates can be enhanced. [0088]
With the provision of the constitution of the touch panel explained in the above-mentioned fourth embodiment, the erroneous operation of the coordinates inputted through the screen can be prevented so that it becomes possible to provide a screen input type display device which can realize a highly reliable screen inputting. [0089]
FIG. 12 is an explanatory view of fabrication steps of the touch panel used in the screen input type display device of the present invention. In the drawing, numeral [0090] 20 indicates a lower substrate processing step, numeral 30 indicates an upper substrate processing step, numeral 40 indicates an assembling step, and numeral 50 indicates an inspection step.
In the lower [0091] substrate processing step 20, after cleaning a received glass on which an ITO film has been already formed as a lower resistance film by a cleaning machine, spacers (dot spacers in this step) are printed on the glass by a printing machine. A conductive paste made of silver (Ag) paste or the like is printed on both ends (see the above-mentioned embodiments) of the glass substrate so as to form inter-substrate connection wiring, lower wiring electrodes and pull-around wiring.
Thereafter, an inoperable region forming member ([0092] 14 in FIG. 19) is printed around an input region. Conductive pressure sensitive adhesive members are laminated using a tape laminating machine and then pressure sensitive adhesive tapes 15 are laminated thus obtaining a lower substrate.
In processing an upper substrate, a received PET film provided with an ITO film as an upper resistance film is cut into a given size by a film cutter and cut films are cleaned and are subjected to an annealing treatment. Thereafter, a conductive paste such as a silver paste or the like is printed on the film to obtain the upper substrate. Here, with respect to the example as explained in the embodiment shown in FIG. 10 in which the conductive pressure sensitive adhesive members are directly adhered to the upper substrate this silver paste printing step is omitted. [0093]
In the assembling [0094] step 40, the produced upper and lower substrates are laminated to each other by a laminating machine and are subjected to the pressure sensitive adhesion while setting a given gap therebetween. After performing the pressure sensitive adhesion, the laminated substrates are cut into a product size using a cutting machine and, as a final step, an FPC which constitutes a signal output terminal is adhered to the cut piece with pressure so as to complete a touch panel. The completed touch panel is transported to an inspection step where the completed touch panel is checked with respect to given inspection items.
In the above-mentioned embodiments, although the explanation is made with respect to the case in which the inter-substrate connection wiring electrodes and the pull-around wiring are formed on the lower substrate side, these may be formed on the opposite-side substrate, that is, the upper substrate side. Further, the electric connection of these components to the FPC may be performed at the upper substrate side. In this case, the pull-around wiring to the FPC and the inter-substrate wiring electrodes which connect the lower resistance film to the upper substrate may be formed on the upper substrate, and they may be electrically connected to each other using pressure sensitive tapes similar to those of the above-mentioned embodiment. [0095]
One embodiment of an entire constitution of a screen input type display device of the present invention which incorporates the touch panel produced in the above-mentioned manner therein is explained in detail in conjunction with FIG. 13 to FIG. 17. [0096]
FIG. 13 is a cross-sectional view for explaining one embodiment using a liquid crystal display device as a screen input type display device of the present invention. In this embodiment, an auxiliary [0097] light source device 200 which includes a light guide body 201 and a linear lamp 202 and a touch panel 100 are mounted on a reflection type liquid crystal panel 300.
A [0098] reflection layer 302 made of an aluminum thin film, a protective film 303 made of a reflection prevention film such as SiO2 or the like and a lower electrode (signal electrode) 304 made of a transparent conductive film such as ITO or the like are formed on an inner surface of a first substrate 301 which constitutes a lower substrate of the liquid crystal panel 300.
Further, on an inner surface of a [0099] second substrate 305 which constitutes an upper glass substrate, color filters 306 of three colors (R, G, B) which are formed by doping dye or pigment into an organic resin film, a protective film 307 made of organic material which prevents impurities from being mixed into a liquid crystal layer 309 from the color filters 306 and flattens an inner surface of the second substrate 305 and an upper electrode (scanning electrode) 308 made of a transparent conductive film such as ITO or the like are formed.
Here, grid-like or stripe-like light-shielding films (black matrix) are formed among respective colors R, G, B which constitute the [0100] color filters 306 when necessary and the protective film 307 is formed on the light-shielding films.
A [0101] liquid crystal layer 309 made of a liquid crystal composite is inserted between the first and second substrates 301, 305 and is sealed by seal material 310 made of epoxy resin or the like thus constituting a liquid crystal display panel.
On a surface of the [0102] second substrate 305 of the liquid crystal panel, a polarizer 312 b, a first phase difference plate 312 c and a second phase difference plate 312 d are laminated. Between each two of the second substrate 305, the polarizer 312 b, the first phase difference plate 312 c and the second phase difference plate 312 d, adhesive layers 311, 311 a made of an adhesive agent (for example, epoxy-based or acrylic-based adhesive agent), pressure sensitive adhesive material or the like is formed so as to fixedly secure respective members.
Here, the adhesive agent means an adhesive agent with which even when two [0103] optical films 312 of various kinds which are once laminated are peeled off, such optical films 312 can be laminated to each other again. By fixing various optical films 312 and the liquid crystal panel using such an adhesive agent, when the optical film 312 and the liquid crystal panel are fixed erroneously, the optical films 312 and the liquid crystal panel are reproducible so that the yield of fabrication can be enhanced.
The [0104] reflection layer 302 may preferably have the mirror reflection characteristics in view of the reflectance. In this embodiment, an aluminum film is formed by a vapor deposition technique. A multi-layered film may be formed on the surface of the reflection layer 302 for enhancing the reflectance. Further, a protective film 303 is formed on the reflection layer 302 for the purpose of protecting the reflection layer 302 from erosion and of flattening the surface of the reflection layer 302.
Here, the reflection layer is not limited to an aluminum film and may be a metal film made of chromium or silver or a non-metallic film so long as the film has the mirror reflection characteristics. [0105]
Further, the [0106] protective film 303 is not limited to the SiO2 film and may be any insulation film which can protect the reflection layer 302. That is, an inorganic film such as a silicon nitride film or the like, an organic metal film such as an organic titanium film or the like or an organic film made of polyimide or epoxy resin or the like may be used. Particularly, the organic film made of polyimide or epoxy resin or the like exhibits an excellent flatness and hence, a lower electrode 304 which is formed on the protective film 303 can be easily formed. Further, when the organic metal film such as the organic titanium film or the like is used as the protective film 303, it becomes possible to form the lower electrode 304 at high temperature so that the wiring resistance of the lower electrode 304 can be decreased.
Above the liquid crystal panel which mounts the multi-layered [0107] optical films 312, an illumination device which includes a light guide body 201 and a light source 202 is disposed as an auxiliary illumination device 200 which is used when the external light is insufficient.
The [0108] light guide plate 201 is made of a transparent resin such as acrylic resin and a print patterning or a surface irregularity processing is applied to a viewer side surface (upper surface) of the light guide plate 201 to make a light L4 of the light source 202 irradiated toward the liquid crystal panel side.
Further, on the [0109] auxiliary illumination device 200, a touch panel 100 is mounted. In this touch panel 100, when the surface of the touch panel 100 is pushed with a rod-like body having a sharpened tip such as a nib or a fingertip, the coordinates of a position corresponding to a pushed portion is detected and data signals to be transmitted to a host (550 in FIG. 17 which will be explained later) of an information processing device (547 in FIG. 17 which will be also explained later) are outputted.
The [0110] second substrate 305 of the liquid crystal panel 300, the light guide body 201 of the auxiliary light source device 200 and the touch panel 100 are fixedly secured to each other by a pressure sensitive adhesive double coated tape (for example, nonwoven fabric impregnated with a pressure sensitive adhesive agent) or the like.
With the use of the pressure sensitive adhesive double coated tape, after the [0111] liquid crystal panel 300, the auxiliary light source device 200 and the touch panel 100 are laminated to each other, it is possible to peel off them and hence, even when the liquid crystal panel 300, the auxiliary illumination device 200 and the touch panel 100 are erroneously fixed, they can be reproduced.
This [0112] auxiliary illumination device 200 is not always necessary and is unnecessary in an environment which is always bright.
In this embodiment, the adhesive layer [0113] 311 a which is disposed between the first phase difference plate 312 c and the second phase difference plate 312 d is provided with a light diffusion function. To be more specific, light diffusion material having a refractive index different from that of the adhesive agent is mixed in the adhesive agent. When an epoxy resin-based adhesive agent or an acrylic-based adhesive agent is used as the adhesive material, transparent organic particles made of polyethylene, polystyrene, divinylbenzene or transparent inorganic particles made of silica or the like can be used as the light diffusion material.
Here, as the adhesive material, pressure sensitive adhesive material having the refractive index different from that of the light diffusion material can be used. In this case, even when the first [0114] phase difference plate 312 c and the second phase difference plate 312 d are erroneously laminated to each other, it is possible to reproduce them.
With the use of the transparent organic particles or inorganic particles as the light diffusion material, the absorption in the visible light region can be reduced and hence, the reflectance and the spectral characteristics of the liquid crystal panel can be improved. [0115]
Further, when the organic-based material is used as the adhesive agent, by using the organic particles as the light diffusion material, the difference of thermal expansion coefficient between them can be decreased so that the occurrence of cracks in the adhesive layer [0116] 311 a can be prevented.
Although cracks are liable to occur in the adhesive layer by mixing the light diffusion material in the adhesive agent compared to the case which uses only the adhesive material, by inserting the adhesive layer [0117] 311 a containing the light diffusion material therein between the first phase difference plate 312 c and the second phase difference plate 312 d having the substantially same thermal expansion coefficient, a problem that cracks occur in the adhesive layer 311 a can be obviated.
Subsequently, The display principle of the constitution shown in FIG. 13 is explained. An incident light L[0118] 1 which is incident on the liquid crystal display device 400 from various directions reaches the reflection layer 302 after passing the touch panel 100, the light guide plate 201 of the auxiliary illumination device 200, the polarizer 312 b, the adhesive layer 311 which is provided for fixing the polarizer 312 b to the first phase difference plate 312 c, the first phase difference plate 312 c, the adhesive layer 311 a having a light diffusion function which is provided for fixing the first phase difference plate 312 c to the second phase difference plate 312 d, the second phase difference plate 312 d, the adhesive layer 311 which is provided for fixing the second phase difference plate 312 d to the second substrate 305, the second substrate 305, the color filters 306, the upper electrode 308, the liquid crystal layer 309 and a specified pixel electrode (or a specified signal electrode) 304 a.
The external light L[0119] 1 which has reached the reflection layer 302 is reflected to become a reflection light L2 and the reflection light L2 reaches the adhesive layer 311 a having a light diffusion function through a path inverse to the path of the incident light L1. The reflection light L2 which has entered the adhesive layer 311 a is scattered in various directions to generate scattering lights L3.
The direct reflection light L[0120] 2 and the scattering lights L3 irradiated from the adhesive layer 311 a are emitted to the outside of the liquid crystal display device 400 after passing the first phase difference plate 312 c which compensates for the phase difference generated when the light passes the liquid crystal layer 309 by making use of the birefringence effect, the adhesive layer 311, the polarizer 312 b, the light guide plate 201 and the touch panel 100.
The viewer can recognize the display controlled by the specified [0121] pixel 304 a by observing the direct reflection light L3 emitted to the outside of the liquid crystal display device.
FIG. 14 is a cross-sectional view for explaining other embodiment of the screen input type display device of the present invention. Parts indicated by the same numeral in FIG. 13 corresponds to parts having identical functions. In this embodiment, an auxiliary [0122] light source device 200 similar to the device explained in conjunction with FIG. 13 is laminated on the liquid crystal panel 300 and a touch panel 100 is mounted on the auxiliary light source device 200 thus constituting a screen input type liquid crystal display device 400.
The [0123] liquid crystal panel 300 is a thin film transistor (TFT) type liquid crystal panel which is a typical example of an active matrix type. A plurality of pixels each of which has a thin film transistor TFT1 and a pixel electrode 304 a are formed on the inside of a first substrate 301 which constitutes the liquid crystal panel 300.
Each pixel is arranged in a region where two neighboring scanning signal lines and two neighboring video signal lines cross each other. The thin film transistor TFT[0124] 1 is constituted of a first semiconductor layer (channel layer) AS which is formed on the first substrate 301, a second semiconductor layer (semiconductor layer doped with impurity) r0 formed on the first semiconductor layer AS and a source electrode SD1 and a drain electrode SD2 formed on the second semiconductor layer r0. Here, although the source electrode SD1 and the drain electrode SD2 are respectively formed of a multi-layered film made of conductive films r1 and r2, the source electrode SD1 and the drain electrode SD2 may be formed of a single-layered film made of only the conductive film r1.
Although the relationship between the source electrode and the drain electrode becomes inverse depending on the manner of applying a voltage, that is, the electrode SD[0125] 2 becomes the source electrode and the electrode SD1 becomes the drain electrode, the electrode SD1 is set as the source electrode and the electrode SD2 is set as the drain electrode in a following explanation for facilitating the understanding of the invention.
In the drawing, PSV[0126] 1 indicates an insulation film (protective film) which protects the thin film transistor TFT1, numeral 304 a indicates the pixel electrode, ORI1 and ORI2 respectively indicate orientation films for orienting a liquid crystal layer 309 which is brought into contact with the first substrate 301 side and a second substrate 305 side, and numeral 308 indicates an upper electrode (common electrode).
BM indicates a light shielding film which is also called a black matrix. The light shielding film BM has a function of enhancing the contrast by shielding light between neighboring [0127] pixel electrodes 304 a. Numeral 310 indicates a conductive film which makes the upper electrode 308 electrically connected to a terminal (multi-layered metal conductive film made of g1, g2, r1, r2 and r3) formed on the first substrate 301.
In the thin film transistor TFT[0128] 1, as in the case of an insulation-gate-type field-effect transistor, when a selective voltage is applied to a gate line voltage GT, the source electrode SD1 and the drain electrode SD2 are electrically connected and hence, the thin film transistor TFT1 functions as a switch.
The [0129] pixel electrode 304 a is connected to the source electrode SD1, the video signal line is connected to the drain electrode SD2, and the scanning signal line is connected to the gate electrode GT. Depending on the selective voltage applied to the scanning signal line, the specified pixel electrode 304 a is selected and a gradation voltage applied to the video signal line is supplied to the specified pixel electrode 304 a. A CST formed of a conductive film g1 constitutes a capacity electrode and has a function of holding the gradation voltage supplied to the pixel electrode 304 a by a next selection period.
This active matrix type [0130] liquid crystal panel 300 is provided with the switching element such as the thin film transistor or the like for each pixel and hence, a problem that a crosstalk is generated between different pixels can be obviated and it is unnecessary to suppress the crosstalk by a special drive such as a voltage equalization method whereby the multi-gradation display can be realized. Further, the active matrix type liquid crystal panel 300 has other features including a feature that the contrast is not decreased even when the number of scanning lines are increased.
In this embodiment, the [0131] pixel electrode 304 a is constituted of a reflection metal film made of aluminum, chromium, titanium, tantalum, molybdenum or the like. Further, since the protection film PSV1 is disposed between the pixel electrode 304 a and the thin film transistor TFT1, even when the pixel electrode 304 a is made large and eventually is superposed on the thin film transistor TFT1, the erroneous operation can be prevented whereby the liquid crystal panel having high reflectance can be realized.
Further, this liquid crystal panel is not provided with the first phase difference plate which is used in the liquid crystal panel of a form explained in FIG. 13 and instead is provided with a third [0132] phase difference plate 312 e for improving the visual angle characteristics. This third phase difference plate 312 e is also called a visual angle enlargement film and improves the angle dependency of the display characteristics of the liquid crystal panel by making use of the birefringence characteristics.
The third [0133] phase difference plate 312 e can be constituted of an organic resin film made of polycarbonate, polyacrylate, polysulfone or the like and hence, by using a light diffusion adhesive layer 311 a as an adhesive layer for fixing the third phase difference plate 312 e to the second phase difference plate 312 d, the occurrence of the cracks in the light diffusion adhesive layer 311 a can be prevented.
FIG. 15A to FIG. 15E are views as viewed from five directions for explaining the outer appearance of a screen input type display device according to the present invention, wherein FIG. 15A is a front view as viewed from a display surface side, FIG. 15B is an upper side view, FIG. 15C is a lower side view, FIG. 15D is a left-side side view, and FIG. 15E is a right-side side view. [0134]
In FIG. 15A to FIG. 15E, numeral [0135] 318 indicates an upper case (shield case) constituted of a metal plate made of stainless steel, iron, aluminum or the like and numeral 320 indicates a first opening which constitutes a display window formed on the upper case 310. Numeral 319 indicates a lower case constituted of a metal plate made of stainless steel, iron, aluminum or the like or plastic such as polycarbonate, ABS resin or the like.
[0136] Numeral 321 indicates pawls formed on the upper case 318 and numeral 322 indicates hooks formed on the lower case 319. The upper case 318 is connected to the lower case 319 by pressing the lower case 319 to the upper case with the engagement of the pawls 321 and the hooks 322.
[0137] Numeral 201 indicates a light guide plate made of transparent material such as acrylic resin, glass or the like, numeral 202 indicates a light source (lamp) such as a fluorescent lamp, a LED or the like. They constitute an auxiliary light source device 200 (here, a front light) which illuminates the liquid crystal panel 300 when an external light is insufficient. Numeral 100 indicates a touch panel for inputting data to be transmitted to a host (information processing part) connected to a liquid crystal display device 400.
[0138] Numeral 312 indicates optical films such as a light diffusion layer, a polarizer, a phase difference plate and the like which are formed on a display part of the liquid crystal display device 400. To make the entire thickness of the liquid crystal display device thin, these optical films are designed such that they are accommodated in a region of an opening of the upper case 318.
FIG. 16A to FIG. 16D are cross-sectional views of an essential part of FIG. 15A to FIG. 15E, wherein FIG. 16A is a cross-sectional view taken along a line A-A of FIG. 15A, FIG. 16B is a cross-sectional view taken along a line B-B of FIG. 15B, FIG. 16C is a cross-sectional view taken along a line C-C of FIG. 15C, and FIG. 16D is a cross-sectional view taken along a line D-D of FIG. 15D. [0139]
The liquid crystal panel is fabricated such that the [0140] first substrate 301 and the second substrate 305 are laminated to each other, the liquid crystal is injected in a gap formed by such lamination and thereafter an injection opening is sealed by sealing material 331. An opening 323 is formed in a portion of the upper case 318 which corresponds to the sealing material 331 so that even when the sealing material is protruded, the expansion of the size of the contour of the liquid crystal panel can be prevented.
On the peripheries of the [0141] first substrate 301 and the second substrate 305, a printed circuit board (scanning line drive PCB) 330 for driving scanning lines which mounts a scanning line drive IC chip 328 is arranged. The printed circuit board 330 is connected to the liquid crystal panel through a flexible printed circuit board 329.
Further, on the peripheries of the [0142] first substrate 301 and the second substrate 305, a printed circuit board (signal line drive PCB) 333 for driving signal lines which has a flexible printed circuit board 329, mounts a signal line drive IC chip 332 and is connected to the liquid crystal panel is arranged.
Various signals and voltages for display are supplied to the scanning [0143] line drive PCB 330 and the signal line drive PCB 333 from an external circuit (host) through an interface connector 324. Here, although an interface connector 324 is provided to the scanning line drive PCB 330, the interface connector 324 may be formed on the signal line drive PCB 333.
[0144] Numeral 326 indicates a spacer for fixing the scanning line drive PCB 330 and numeral 327 indicates a spacer for pressing connection portions which connect the scanning line drive PCB 330 and the signal line drive PCB 333 to the liquid crystal panel. These spacers are constituted of insulation resilient material such as rubber or the like.
[0145] Numeral 325 indicates a pressure sensitive adhesive double coated tape and a non-woven fabric impregnated with epoxy-based adhesive agent can be used as such a tape 325, for example. With the use of the pressure sensitive adhesive double coated tape 325, the upper case 318 is fixed to the liquid crystal panel, the upper case of the liquid crystal panel is fixed to the light guide plate 201 of the auxiliary light source device 200, and the light guide plate 201 of the auxiliary light source device 200 is fixed to the touch panel 100.
In this manner, by fixing the liquid crystal panel, the auxiliary [0146] light source device 200 and the touch panel 100 using the pressure sensitive adhesive double coated tape 325, the assembling operation can be simplified and the reproduction after the erroneous assembling is facilitated so that the fabrication yield can be enhanced.
An inwardly protruding portion [0147] 319 a is formed on the lower case 319 which provides an integration of the liquid crystal panel together with the upper case 318. This protruding portion 319 a resiliently holds the liquid crystal panel.
FIG. 17 is an explanatory view of one example of an information processing device which uses the screen input type display device of the present invention. This image processing device is also called a so-called “portable information terminal” and is constituted of a [0148] body part 547 and a display part 548. The body part 547 includes a keyboard 549, a host (information processing part) 550 having a microcomputer 551 and a battery 552.
The above-mentioned push input type liquid [0149] crystal display device 400 is mounted on the display part 548 and characters or devices 558 are inputted on the touch panel exposed at the display part or icons 559 displayed on the display part are selected using a pen 556 accommodated in a pen accommodating part 557.
Further, an [0150] inverter power source 554 is mounted on the display part 548 for supplying a lighting power to the auxiliary light source device through a cable 555.
Signals and voltages for display from the main part are supplied to an [0151] interface connector 324 of the above-mentioned liquid crystal panel which constitutes the liquid crystal display device 400 mounted on the display part 548 through an interface cable 553.
Further, this information processing device can be connected to a [0152] portable telephone 560 through a cable 561 so that communication can be performed by connecting the information processing device to an information communication network such as Internet.
In this manner, with the use of the screen input type display device of the present invention, the information processing device can be miniaturized and light-weighted so that the availability of the device can be enhanced. [0153]
The shape and the structure of this type of portable information terminal are not limited to those described in the drawing and the portable information terminals having versatile shapes, structures and functions can be considered. [0154]
As has been described heretofore, according to the present invention, it becomes possible to provide a highly reliable image input type display device having a touch panel which can eliminate the erroneous operation for detection of coordinates by stabilizing the linearity of the resistance value detection of the resist films. [0155]

Claims

What is claimed is:

1. A screen input type display device which arranges a touch panel on a display surface of a display device, the touch panel comprising:

a first substrate having a first resistance film,

a second substrate having a second resistance film,

an inter-substrate connection wiring electrode being formed on the second substrate, and

a conductive pressure sensitive adhesive member being disposed between the first resistance film and the inter-substrate connection wiring electrode, the conductive pressure sensitive adhesive member electrically connecting the first resistance film and the inter-substrate connection wiring electrode, and the conductive pressure sensitive adhesive member having pressure sensitive adhesive material in which conductive particles are mixed formed on both surfaces of a metal foil for laminating the first substrate and the second substrate.

2. A screen input type display device according to

claim 1

,

wherein the first resistance film and the conductive pressure sensitive adhesive member are directly brought into contact with each other.

3. A screen input type display device according to

claim 1

,

wherein a first wiring electrode formed on the first resistance film is interposed between the first resistance film and the conductive pressure sensitive adhesive member.

4. A screen input type display device according to

claim 1

,

wherein the metal foil is a copper foil.

5. A screen input type display device according to

claim 1

,

wherein the conductive particles are metal particles.

6. A screen input type display device according to

claim 1

,

wherein the conductive particles are plastic particles to which a conductive metal plating is applied or glass particles to which a conductive metal plating is applied.

7. A screen input type display device according to

claim 1

,

wherein the conductive particles at the first substrate side of the metal foil and the conductive particles at the second substrate side of the metal foil are different in kind from each other.

8. A screen input type display device according to

claim 1

,

wherein the first substrate is formed of a soft film member and the second substrate is formed of a hard plate.

9. A screen input type display device according to

claim 1

,

wherein one of the first substrate and the second substrate is formed of a soft film member and the other is formed of a hard plate, the conductive particles at the hard plate side of the metal foil are formed of plastic particles to which a conductive metal plating is applied and the conductive particles at the soft film member side of the metal foil are formed of metal particles.

10. A screen input type display device which arranges a touch panel on a display surface of a display device, the touch panel comprising:

a first substrate having a first resistance film,

a second substrate having a second resistance film,

a conductive pressure sensitive adhesive member being disposed between the first resistance film and the inter-substrate connection wiring electrode, the conductive pressure sensitive adhesive member electrically connecting the first resistance film and the inter-substrate connection wiring electrode, and the conductive pressure sensitive adhesive member having pressure sensitive adhesive material in which plastic particles to which a conductive metal plating is applied are mixed for laminating the first substrate and the second substrate.

11. A screen input type display device according to

claim 10

,

12. A screen input type display device according to

claim 10

,